This invention relates to automotive wheels for supporting thereon pneumatic tires, and more particularly to an improved such wheel which enables the wheel to continue to operate safetly even after the associated pneumatic tire is no longer inflated, but tends to become flat because of a puncture or the like. More particularly this invention relates to an improved combination of a wheel and associated runflat device which eliminates any undesirable relative motion between the wheel and the runflat device when in use.
Heretofore a number of efforts have been made to provide a satisfactory safety or runflat device for tubeless tires. Unfortunately, in many such devices, as shown for example in U.S. Pat. Nos. 3,049,162, 2,040,645 and 3,635,273, the runflat devices merely comprise annular or ring-shaped devices which are rotatably or moveable mounted on a tire rim for engagement by the inner peripheral surface of a tubeless tire when the latter becomes deflated. Although some such prior devices such as disclosed in U.S. Pat. Nos. 1,379,915 and 3,420,288 proposed to secure the ring-shaped safety device on the tire rim in a snug manner so that the device normally does not rotate relative to the tire rim, nevertheless, such efforts are not very effective in practice, since heavy braking or driving on rough surfaces can cause relative movement between the tire rim and the associated runflat device. This undesirable relative rotation upsets the balancing of the wheel and the tire. In practice, when a runflat device is inserted into a tire and installed upon a wheel, it is customary that an assembly be balanced in a traditional fashion. As long as the runflat device does not move on the wheel, the tire and wheel of the assembly will remain balanced. However, heavy braking or travel on rough bumpy surfaces could cause undesirable relative movement between the wheel and surrounding runflat device, thus causing the formerly balanced wheel to be subjected to undesirable vibration or shimmy which generally is associated with the movement of the runflat device inside the tire.
While efforts have been made to provide runflat devices which are secured against rotation relative to the wheel upon which they are mounted, such as for example as disclosed in U.S. Pat. Nos. 2,241,858, 3,394,749 and 4,573,509, these devices are rather complicated to assemble and difficult to manufacture. Moreover, many such efforts to secure the runflat device against movement on the wheel employ cam locks, bolts, or elastic bands, or the like, which have the disadvantage that each such devices can be installed incorrectly, resulting in the condition that allows the runflat device to move on the wheel, thus leading to the above-noted unbalanced condition of the wheel.
Accordingly, it is an object of this invention to provide a combined wheel and runflat device which permanently eliminates the possibility of the free spinning or movement of the runflat device relative to the wheel, during operation of the associated automotive vehicle.
Still another object of this invention is to provide an improved runflat and wheel product of the type described which are relatively simple and inexpensive to manufacture, and which during assembly cannot be incorrectly installed one relative to the other in any manner which might interfere with the air valve of the associated tire.
More specifically, it is an object of this invention to provide on a wheel of the type described one or more fences which engage the associated runflat device to eliminate any possibility of movement of the runflat during operation of an associated vehicle.
Other objects of the invention will be apparent from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.
An annular runflat device is formed of two semi-annular sections that are removably secured coaxially upon and surround the annular, drop-center section of a metal tire rim. The outer peripheral surface of the runflat device is disposed normally to be spaced radially inwardly of the inner peripheral surface of a properly inflated tubeless tire mounted on the rim, but is disposed to be engaged with the inner peripheral surface of the tire when the latter is operated in a deflated or run-flat mode. To prevent any relative movement between the runflat device and the rim, the rim has projecting from its outer peripheral surface adjacent one end of its drop-center section a plurality of lugs or fences that are secured to or integral with the rim at angularly spaced points about its axis. The runflat device has integral with and projecting axially beyond one end thereof a circumferential flange the inner peripheral surface of which overlies said plurality of fences, and which has therein a like plurality of recesses in each of which one of said fences is seated to prevent rotational and axial movement of said runflat device relative to said rim.